Perhaps you should try some spelling variations:
sach gia » sach giao, cach giao, bach giao
duc khoa » duoc khoa, duc hoa, dac khoa
khoa hoc » hoa hoc
sam quan » nam quan, sau quan, tam quan
san quan » van quan, ban quan, dan quan
te sach » toc sach
gia duc » giao duc, gia muc, gia thuc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach gia duc khoa hoc - stem. ((sam quan) or (san quan)) nam~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach gia duc khoa hoc - stem. ((sam quan) OR (san quan)) nam.
• Adding a wildcard symbol may retrieve word variants: te sach gia duc khoa hoc - stem. ((sam quan) or (san quan)) nam*.